Clutches for vehicles, as known today, can be classified in two main groups: solid clutches and fluid clutches.
A solid clutch is one which uses friction surfaces to transmit torque progressively from input shaft to output shaft. The disadvantages of such clutches are:
Friction surfaces suffer overheating and wearing out. PA1 Low efficiency at intermediate positions. PA1 In general, it is difficult to make them automatic. PA1 They are expensive PA1 They are bulky PA1 They present efficiency PA1 It has no friction surfaces. Therefore, there is no wearing to repair, no friction disks to replace. It must be noted that, to replace the disk or a conventional solid clutch, it is necessary to take the motor apart. This job is as expensive as the disk itself. PA1 It is as automatic as a fluid one, but very much simpler and, therefore, cheaper. PA1 It has zero slip in the "closed" position. This means that no wasting of power exists. PA1 a) Displaceable friction surfaces, such as disks, cones, pulleys, etc. PA1 b) Displaceable gears. PA1 c) A combination of epicycloidal gears, internal clutches and internal brakes, manually commanded (Wilson gear box). PA1 d) The same as c) but automatically commanded (Hydramatic box). PA1 e) A combination of d) and a hydraulic torque converter (Power Glide Box). PA1 a) Abandoned many years ago, due to its low efficiency, high wearing out and unsuitability to transmit power beyond certain limits. PA1 b) In use but it needs a pedal commanded clutch and special fixtures to synchronize the gears before they mesh. The "synchronizers" do not have a long life. PA1 c) Abandoned many years ago, maybe on account of its excessive complications to give four speeds. PA1 d) Good but too complicated. PA1 e) Complicated; low efficiency. PA1 It is a complete transmission in which both clutch and gear box are completely mechanical. Neither electric nor electronic circuits and neither hydraulic nor pneumatic systems are required. PA1 The clutch has neither friction surfaces nor fluids to transmit torque. The gear box has no friction surfaces in the set of mechanisms which gives the position DRIVE. PA1 All forwards gears are in constant mesh. PA1 Flexibility of the gear box is such that it may automatically effect 50 or 100 speeds changes per minute, for instance, without suffering special wearing out or impacts and without producing noises. PA1 The gear box presents only three speeds, but it can change directly from 3rd to 1st speed (or vice-versa), if so required, again without special wear, impacts or noise. PA1 Its construction is relatively simple, so its cost is low in comparison with standard automatic boxes. PA1 The entire transmission is elastic, being able to absorb vibrations of great amplitude.
A fluid clutch is one which uses a special fluid to transmit torque from input to output shaft. The disadvantages of such clutches are:
Respecting this last point, it is necessary to go deeper: Manufacturers mention that these fluid clutches slip only 5%. Nevertheless, that 5% slip represents also 5% of the total power developed by the motor and this loss of power must be evacuated by means of heat sinking "fins" on the clutch case. If we suppose that we are using a motor that develops only 40 HP, that 5% means 1472 watts which, in turn, is the equivalent of a 3 bar electric stove which the driver must carry "ON" everywhere he goes, thus heating the environment at his own cost. This fact, exposed as above, would make any potential buyer desist.
The prior art problems solved by the clutch forming part of this invention are:
NOTE: This clutch is also useful for decreasing the starting current of electric motors that must start assuming heavy loads (cranes, tramways, etc.).
Gear boxes for vehicles, as known today, can be grouped in five mean systems, working by:
Disadvantages of the above mentioned systems are, respectively:
The gear box forming part of this invention keeps all its forward gears in constant mesh. The motor itself makes the speed changes, choosing the suitable speed at any moment. Of course, the invention uses, in any case, a lever to permit the driver to choose among REVERSE--NEUTRAL--DRIVE positions. There is also a position PARKING that works in a similar fashion to conventional automatic transmissions.
A fifth position has been added, which is not precisely the known position LOW because this speed is not necessary if a car including this invention goes forward (at any slope). That fifth position is used specially to control the vehicle when it goes down and to start the motor by pushing the vehicle. As this fifth position (which we will call DOWN) uses a band brake commanded by the driver, it is also useful to decrease quickly the velocity of the car, given it is possible to enter it at any velocity of the car.
The gear box of this invention presents a great degree of elasticity, much more than any other gear box. The advantage of this condition is clear.